package com.sun.filter;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectWriter;
import com.sun.annotation.RepeatSubmit;
import com.sun.utils.AjaxResult;
import com.sun.utils.ServletUtils;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;

/**
 * 防止重复提交拦截器
 */
@Slf4j
@Component
public abstract class RepeatSubmitInterceptor extends HandlerInterceptorAdapter {

    public static final String DEFAULT_FAIL = "\"Parse failed\"";
    private static final ObjectMapper objectMapper = new ObjectMapper();
    private static final ObjectWriter objectWriter = objectMapper.writerWithDefaultPrettyPrinter();


    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        log.info(">>>>>>>>>>进入到拦截器：preHandle()方法中>>>>>>>>>>>");
        if (handler instanceof HandlerMethod) {
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            //获取方法
            Method method = handlerMethod.getMethod();
            //获取方法上的注解
            RepeatSubmit repeatSubmit = method.getAnnotation(RepeatSubmit.class);
            if (repeatSubmit != null) {
                if (this.isRepeatSubmit(request)) {
                    AjaxResult ajaxResult = AjaxResult.error("不允许重复提交，请稍后再试");
                    ServletUtils.renderString(response, objectMapper.writeValueAsString(ajaxResult));
                    return false;
                }
            }
            return true;
        } else {
            return super.preHandle(request, response, handler);
        }
    }


    /**
     * 验证是否重复提交由子类实现具体的防重复提交的规则
     *
     * @param request
     * @return
     * @throws Exception
     */
    public abstract boolean isRepeatSubmit(HttpServletRequest request) throws Exception;

}
